GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Bonneville 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Cooling Insufficient - Air Conditioning (A/C) System

Step

Action

Value(s)

Yes

No

1

Did you perform the HVAC Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Perform the Recalibrate all Motors command in the instrument panel module Special Functions using the scan tool.
  4. Observe the current DTC list in the instrument panel module using the scan tool.

Does the scan tool display any DTCs?

--

Go to DTC Table

Go to Step 3

3

IMPORTANT: Indicated outside air temperature must be above 16°C (60°F).

  1. Cover the sunload sensor.
  2. Start the engine.
  3. Fully open all panel outlets.
  4. Adjust driver side temperature to 16°C (60°F).
  5. Select PANEL mode.
  6. Set blower speed to maximum.
  7. Turn OFF the passenger HVAC control.

Does the A/C compressor operate?

--

Go to Step 4

Go to HVAC Compressor Clutch Does Not Engage

4

Does the blower operate and provide sufficient airflow?

--

Go to Step 5

Go to Blower Motor Does Not Operate Properly

5

Perform the refrigerant system performance test. Refer to System Performance Test .

Are low and high side pressures within specification?

--

Go to Step 6

Go to VDOT Air Conditioning (A/C) System Diagnosis

6

Check right and left panel temperature sensors for proper installation. Refer to Panel Discharge Sensor Replacement - Left Side and Panel Discharge Sensor Replacement - Right Side .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 7

7
  1. Start the engine.
  2. Fully open all panel outlets.
  3. Adjust driver side temperature to 24°C (75°F).
  4. Select PANEL mode.
  5. Set blower speed to illuminate 2 bars on the fan speed display.
  6. Turn OFF the passenger HVAC control.
  7. Inspect for airflow through the inside air temp sensor by placing a 5 cm (2 in) square piece of paper over the sensor air inlet.

Does the paper stay in place?

--

Go to Step 8

Go to Step 11

8
  1. Turn the engine OFF.
  2. Install a scan tool.
  3. Cover the sunload sensor.
  4. Start the engine.
  5. Adjust driver side temperature to 24°C (75°F).
  6. Turn OFF the passenger HVAC control.
  7. With a scan tool, observe the Right and Left Solar Sensor data parameters in the instrument panel module Open/Short Data list.

Does the scan tool indicate that both the right and left solar sensor parameters are greater than the specified value?

230 Counts

Go to Step 9

Go to Step 17

9
  1. Uncover the sunload sensor.
  2. Direct a light source at the right and then the left side of the sunload sensor.

Do the counts change similarly and correspond to the proper side of the sunload sensor?

--

Go to Step 10

Go to Step 17

10
  1. Install a thermometer near the right panel, left panel and inside air temperature sensors.
  2. With a scan tool, observe the Right A/C Duct Temp, Left A/C Duct Temp and Inside Air Temp data parameters in the instrument panel module HVAC Sensors data list.

Does the scan tool indicate sensor temperatures near the thermometer temperatures within the specified range?

+3°C (5°F) to -3°C (-5°F)

Go to Step 12

Go to Step 15

11

Inspect for a blocked or disconnected aspiration hose.

Did you find and correct the condition?

--

Go to Step 22

--

12

Does the customer need to change the set temperature frequently to maintain comfort?

--

Go to Set Temperature Requires Frequent Adjustment

Go to Step 13

13
  1. Start the engine.
  2. Verify all the instrument panel outlets are open.
  3. Operate the system. Refer to the appropriate procedure:

Does the system operate properly?

--

Go to Step 14

Go to Symptoms

14
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, adjust the Temperature Offset in instrument panel module Special Function/Set Options as needed.

Did you complete the repair?

--

Go to Step 22

--

15

Inspect for poor connections at the harness connector of the suspect temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 16

16
  1. Turn OFF the ignition.
  2. Test the suspect temperature sensor resistance. Refer to Sensor Resistance Table .

Does the resistance measure near the specified value?

--

Go to Step 18

Go to Step 20

17

Inspect for poor connections at the harness connector of the sunload sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

18

Inspect for poor connections at the harness connector of the instrument panel module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 21

19

Replace the sunload sensor. Refer to Sunload and Twilight Sentinel Sensor Replacement in Instrument Panel, Gauges and Console.

Did you complete the replacement?

--

Go to Step 22

--

20

Replace the temperature sensor. Refer to Panel Discharge Sensor Replacement - Left Side and Panel Discharge Sensor Replacement - Right Side .

Did you complete the replacement?

--

Go to Step 22

--

21

Replace the instrument panel module. Refer to Instrument Panel Module Replacement .

Did you complete the replacement?

--

Go to Step 22

--

22

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2